Hidden ancestors traced in modern genomes reshape human family tree
A new method called TRACE lets researchers scan modern human genomes for signals from long-lost populations, uncovering two ghost lineages that contributed to today’s DNA: a younger Africa-related lineage that interbred with Homo sapiens over 50,000 years ago and accounts for about 0.5%–1% of DNA, and a much older “super-archaic” lineage (diverging ~1.8 million years ago) that interbred with Denisovans and reached modern humans via that lineage. The team found traces of both ghost ancestries across populations in Africa, Europe, and Asia, suggesting deep, widespread admixture before the major Out-of-Africa migration. While likely linked to Homo heidelbergensis and Homo erectus candidates, the exact populations remain unknown; the study highlights how deep genealogies can illuminate human history and evolution, with future ancient DNA potentially confirming the lineages.
